Electrodynamic telephone



Oct. 26 1926. 1,604,532

H. RIEGGER ELECTRODYNAMIC TELEPHONE Filed May 15, 1924 2 Sheets-Sheet 2 l/f/f I/f/ //.7

51m/Wdh A purpose to obtain a true reproduction of Cil Patented Oct. 26, 1926.

UNITED STATES PATENT'VOFFICE.

HANS RIEGGER, OF BERLIN-PANKOW, GERMANY, ASSIGNOR TO SIEMENS & HALSKE, AKTIENGESELLSCHAFT, 0F SIEMENSSTADT, NEAR BERLIN, GERMANY,

A CORPORATION 0F GERMANY.

ELECTRODYNAMIC TELEPHONE.

Ap'plication led May 15, 1924, Serial No. 713,481, and in Germany J'une 8, 1923.

This invention relates to improvements in electrodynamic telephones, and has for its music and speech.

My invention consists essentially in providing upon the telephoneI diaphragm, which itself is not concerned in conducting electric currents and the magnetic flux, ribs through which the telephone currents flow and which ribs arc so disposed between'the pole-shoes of the exciter magnets that it is traversed by the magnetic ux. The electric currents and the magnetic field then generate forces which are at right angles to the plane ofthe diaphragm. so that the diaphragm is vibrated. As it is possible to distribute such current carrying ribs all over the surface of a diaphragm, it is possible to exert forces upon the diaphragm, which act fairly uniformly over the entire surface. In this manner undesired deflect-ions of the diaphragm and harmonic oscillations are avoided even when the diaphragm possesses very little stiffness. Any suitable size may be chosen for the diaphragm and the latter need possess no elasticity at all, since it is not called upon to offer resistance to any magnetic forces. In this manner the disturbing natural vibrations are also eliminated, which usually distort the sounds to be reproduced. The possibilitythus afforded to use diaphragms of very large size is particularly advantageous in constructing loud4 speaking telephones. 1

The drawings affixed to this specification and forming part thereof illustrate in Fig. 1 one construction of the improved telephone in cross-section,

Fig. 2 a horizontal section along line A-B of Fig. 1,

Fig. 3 a modified construction in crosssection,

Fig. 4 the same in horizontal section along line C-D of Fig. 3.

Referring to Figs, 1 and 2, it will be seen that on the underside of the diaphragm 1, which may for instance, consist of mica, a sinuous rib 2 is fastened. This rib consists preferably of a strip of aluminium, in order 0 to keep the weight as low as possible. The

telephone currents are le"l to this strip 2 by the conductors 3 and 4. The strip passes along between the magnetic poles 5 insuch a manner, that each longitudinal rib is situthe coil tween t s 6. The diaphragm is clamped behe frame 7 and the cover 8. A rush of current flowing through the aluminium strip produces at all points of the magnetic fields a force of equal size and equal direction, so that the diaphragm rises or falls along its entire extent. The diaphragm may be made of any suitable size, so that in this manner a telephone capable of large volumes of sound is produced.

Referring to Figs. 3 and 4.-, it will be seen that in this construction a series of individual. aluminium strips 12, 13, 14, 15, 16. 17 are fixed upon the underside of the diaphragm 11. The ribs 12, 13 and 14 are traversed by the telephone currents in the same direction and the other three ribs 15, 16 and 17 in oppositev direction. In. correspondence i herewith the first three ribs are traversed by a magnetic field in one direction and the latterv three bv an oppositely directed magnetic. field. The fields are excited by the electroemagnets 18, 19, 20, so that in the middle. for instance, a south pole S and at both sides a north pole N isproduced. The fields pass from pole-shoe 21 across iron bridge 22, the pole-shoe 23 and the yoke 50. The other magnetic field passes from the pole-shoe 24 across the bridge 25. Between the pole-shoes 21, 23 and 24 and the bridges 22 and comp ar to Figs 25 are situated the ribs 12 to 17 As ed with the arrangement according 1 and 2 winding space for the electromagnets is saved by the present construction, so that ample space is available for the exciting coils 26. The pole-shoes 21,

23. 24 and the bridges 22 and 25 together with the diaphragm 11 are fixed in a single frame, and 28.

which consists of the two parts 27 VThis common enclosure in the same frame enables the maintenance of exactspacing between the ribs and the'pole-shoes. The frame with its parts is then inserted as selfcontained unit into the casing 29 with the yoke 50. in which theelectro-magnets 18, 19,

20 are fixed. The ribs are cemented to the diaphragm by means of bent over edges. In order to render the attachment more reliable parts of the edges of the strips may be passed through the diaphragm and bent over on the upper side of the diaphragm.

It wi ll be readily understood that I do not 'limit myself to the exact details of the construction described and shown and that these may be altered Within the scope of my claims Without departing from the spirit of my invention.

AWhat I claim as my invention and desire to secure by Letters Patent is l. In an electrodynamic telephone in comliination a non-conducting non-magnetic diaphragm, a plurality of ribs of suitable material adapted to conduct the telephone currents, said ribs being distributed over the surface of said diaphragm and fixed to it, and means for producing a magnetic field, Whose lines of force cut said ribs in a transverse direction.

2. In an electrodynamic telephone in combination a non-conducting non-magnetic diaphragm, and a plurality of magnets distributed over the area covered by said diaphragm and a rib of suitable material adapted to conduct the telephone currents, said ribs being fixed to said diaphragm and being suitably Wound across the area of said diaphragm Within and transversely to the path of the lines of force of said magnets.

3. In an electrodynamic telephone in combination a mica diaphragm and a plurality of magnete distributed over the area covered by said diaphragm and a rib of suitable material adapted to conduct the telephone currents, said rib being ixed to said diaphragm and being suitably Wound across the area of said diaphragm Within and transversely to the path of the lines of force of said magnets.

4. In an electrodynamic telephone in combination a mica diaphragm, a plurality of aluminum ribs distributed over the surface of said diaphragm and fixed to it and adapted to conduct the telephone currents and magnets suitably disposed adjacent to and within the area of said diaphragm, to cause lines of torce ot said magnets to cut said ribs in a transverse direction.

5. In an electrodynamic telephone in combination a .mica diaphragm and a plurality of magnets distributed over the area covered by said diaphragm and a rib of aluminum adapted to conduct the telephone currents, said rib being fixed to said diaphragm and being suitably Wound across the area of said diaphragm Within and transversely to the path of the lines of force of said mag'- nets.

6. In an electrodynamic telephone in combination a non-conducting non-magnetic diaphragm, a plurality of ribs of suitable material adapted to conduct the telephone currents, said ribs being distributed over the surface of said diaphragm and fixed to it, and magnets disposed adjacent to said diaphragm in suitable polarity sequence with relation to said ribs to cause similarly directed magnetic flux to transversely cross ribs traversed by the current in similar direction.

7 In an electrodynamic telephone in combination a non-conducting non-magnetic diaphragm, a plurality of ribs of suitable material adapted to conduct `the telephone currents, said ribs being distributed over the surface of said diaphragm and fixed to it, and magnets for producing a magnetic field Whose lines of force cut said ribs in a transverse direction and a frame adapted to support and hold said diaphragm and pole shoes for said magnets connected with said frame to Jform a rigid unit therein.

In testimony whereof I afliX my signature.

HANS RIEGGER. 

